Question

16 g of radioactive radon is kept in a container. How much radon will disintegrate in 19 days? Half life of radon is 3.8 days.

• A. 0.5 g
• B. 5.5 g
• C. 10.5 g
• D. 15.5 g

Answer 1

The correct option is D

15.5 g

Number of half lives in 19 days is
$n=\frac{19days}{3.8days}=5$
$\therefore$ Number of atoms left undecayed aftr 19 days is
$N=N_0{\left(\frac{1}{2}\right)}^5=\frac{N_0}{32}=\frac{16g}{32}=0.5g$
Hence the correct choice is (d).